TECHNICAL AREA
[0001] The present application relates cooling of propulsion batteries and in particular
propulsion batteries that may be positioned in several positions or clusters in or
on a vehicle.
BACKGROUND OF INVENTION
[0002] Battery-operated vehicles are provided with propulsion battery packs for providing
enough energy for the operation of the vehicle. Propulsion battery packs are known
to be sensitive to temperature differences in particular when they are combined in
parallel electrical circuits. By keeping all the batteries at even temperatures, the
aging of the batteries can be kept under control. A cooling circuit is then designed
to provide even temperatures. That is, the coolant flow is guided as a parallel flow
to the batteries.
[0003] Usually for battery-operated vehicles, the propulsion battery pack is placed quite
close to the cooling system, including power train and electric machine cooling, radiators,
pumps and valves. For busses the cooling system can be placed in the rear of the vehicle.
Regarding busses for public transport, all propulsion battery packs cannot be placed
in the rear of the vehicle and there is limited space available inside the bus in
the passenger area. Therefore, some of the propulsion battery packs are placed on
the roof of the bus. This poses problems with the coolant distribution from the cooling
system in the rear up to the roof of the vehicle. One problem is that there also is
limited space for conduits for coolant to and from the battery packs on the roof.
[0004] A general concern regarding cooling systems for battery packs is air in the system
that needs to be removed in order for the cooling of the batteries to be efficient.
This is because air bubbles may be trapped in different locations in the battery packs
and the cooling in those locations will thus be inferior, and might risk damaging
cells in the battery due to excessive heat. Air enters the cooling system when the
system is assembled or if repairs are needed whereby the system is opened. Generally,
there are deairing functions built in the cooling system such as expansion tanks connected
at positions in the cooling system where air will gather, such as high points in the
cooling system.
[0005] Regarding the above mentioned locations of battery packs such as on the roof, the
de-airing poses a further problem because of the distance between the main cooling
system and the battery packs. Due to the limited space for conduits, but also due
to added costs, it may not be possible and/or desired to provide extra conduits and
pumps for transporting air in the battery packs to the main cooling system. It would
of course be possible to provide an extra de-airing unit in the vicinity of the battery
packs, but again, this adds costs both regarding the unit as such but also added assembly
time. Further, it would add to the complexity of the system and would also require
additional space adjacent the battery packs, which might not be feasible.
[0006] There is thus room for improvements in this technical area.
BRIEF DESCRIPTION OF INVENTION
[0007] The aim of the present application is to develop arrangements and systems for cooling
propulsion batteries. This aim is solved by an arrangement and a vehicle propulsion
battery cooling system according to the independent patent claims. Preferable embodiments
form the subject of the dependent patent claims.
[0008] According to one aspect, a coolant distribution arrangement for a vehicle propulsion
battery cooling system is provided. The cooling system may comprise a coolant inlet
circuit, a coolant outlet circuit, and at least one coolant branch, configured to
cool a set of propulsion battery packs.
[0009] The arrangement may comprise a first manifold section, which first manifold section
may comprise a coolant inlet configured to receive coolant from the coolant inlet
circuit, supply outlets configured to supply coolant to the at least one coolant branch.
[0010] The arrangement may further comprise a second manifold section, which second manifold
section may comprise receiving inlets configured to receive coolant from the at least
one coolant branch, a coolant outlet configured to return coolant to the coolant outlet
circuit.
[0011] Further, the arrangement may comprise a deairing connection between the first manifold
section and the second manifold section configured to evacuate air from the first
manifold section to the second manifold section.
[0012] With this solution, any air that has entered the inlet circuit and is transported
to the first manifold section, due to for instance repairs wherein the cooling system
is opened, will be transported from the first manifold section via the deairing connection
to the second manifold section, where the air will be transported with the return
flow back to the main cooling system that is provided with appropriate deairing devices.
Also, air that might have entered the battery packs will be transported to the second
manifold section and then follow the return flow back to the main cooling system.
[0013] With this solution, no additional deairing solution is necessary, whereby additional
deairing devices, such as expansion tanks will not be necessary adjacent the arrangement
and the coolant branch or branches with the battery packs. Nor will any additional
deairing conduits be necessary. This is an advantage in particular when battery packs
are placed in locations on the vehicle where it might be difficult or costly to provide
additional deairing solutions, such as for instance when battery packs are placed
remotely from the main cooling system and/or the space available is limited. The solution
is thus cost-effective both regarding omission of additional components as well as
reduced complexity and reduced assembly time.
[0014] According to a further aspect, the deairing connection may be arranged downstream
of the supply outlets of the first manifold section, and in this regard, the deairing
connection, when the arrangement is attached to a vehicle, may be positioned higher
than the supply outlets. Thus, any air in the first manifold section will be transported
with the flow of coolant to the deairing connection, reducing the risk of air entering
the outlets to the battery packs and reaching the battery packs. Further in this regard,
the coolant inlet may be arranged upstream of the supply outlets. This provides the
advantage that there is a pressure drop in the first manifold section, in turn providing
an equalized flow of coolant through all the outlets and thus an equalized flow through
the battery packs, which in turn provides the same cooling in all the battery packs.
[0015] According to a further aspect, the deairing connection may be arranged downstream
of the receiving inlets of the second manifold section. In this regard, the deairing
connection may be arranged upstream of the coolant outlet, whereby air in the second
manifold section is evacuated through the coolant outlet. Thus, both air from the
deairing connection and any air from the battery packs will be transported by the
flow of coolant through the coolant outlet and back to the main cooling system. Further
in this regard, the coolant outlet, when the arrangement is attached to a vehicle,
is positioned higher than the deairing connection. This ensures that any air in the
second manifold section will rise to the upper part where the coolant outlet is positioned.
[0016] As one option, the first and the second manifold sections may be discrete components
and wherein the deairing connection comprises a separate conduit. This may be an advantage
if the space available is such that it is difficult to provide it as a single unit.
As another option, the first and the second manifold sections may form a single unit
and wherein the deairing connection comprises a passage provided in the unit. If available
space allows it, then a single unit might be a good option, reducing the number of
components and thus assembly time and cost.
[0017] According to a further aspect, a vehicle propulsion battery cooling system is provided,
comprising at least one distribution pipe circuit fluidly connected to a main cooling
system, at least one coolant circuit configured to cool a set of propulsion battery
packs, and a coolant distribution arrangement as described above.
[0018] With such a vehicle propulsion battery cooling system, several distribution pipe
circuits may be fluidly connected in series or in parallel to the main cooling system.
It is thus possible to have several places on the vehicle where battery packs are
positioned, such as on several locations on a roof of a buss, such as an articulated
buss, and still utilize the benefits of the solution. Thus, the at least one distribution
pipe circuit and the battery packs may be located remotely from the main cooling system,
and actually quite far from the main cooling system. That can for example be the case
where battery packs have to be arranged several meters higher up and farther away
from the main cooling system. One example here is busses for public transport where
the main cooling system often is placed in the rear part of the buss while several
battery packs have to be placed on the roof due to the limited space inside the bus.
This is even more pronounced with articulated busses where some battery packs are
arranged on the roof of the front part while some battery packs are arranged on the
roof of the rear part.
[0019] The solution may thus comprise a single coolant inlet circuit and a single coolant
outlet circuit for fluid connection between the main cooling system and the distribution
pipe circuit. Thus, as a minimum, only two conduits are required for providing adequate
cooling of battery packs even when placed remotely from the main cooling system and
even if more than one cluster of battery packs are to be cooled.
[0020] These and other aspects of, and advantages with, the present invention will become
apparent from the following detailed description of the invention and from the accompanying
drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0021] In the following detailed description of the invention, reference will be made to
the accompanying drawings, of which
Fig. 1 schematically shows a distribution pipe circuit, comprising a coolant distribution
arrangement, to be fluidly connected to a main cooling system of a vehicle as well
as being fluidly connected to propulsion battery packs,
Fig. 2 schematically shows two distribution pipe circuits according to Fig. 1 fluidly
connected in series,
Fig. 3 schematically shows two distribution pipe circuits according to Fig. 1 fluidly
connected in parallel,
Fig. 4 schematically shows an example of a coolant distribution arrangement that may
be comprised in the distribution pipe circuit of Fig. 1, and
Figs. 5-8 schematically show different vehicles provided with propulsion battery pack
cooling systems comprising the distribution pipe circuit with the coolant distribution
arrangement.
DETAILED DESCRIPTION OF THE INVENTION
[0022] In this application, "cooling system", "coolant" and "cooling" is used in connection
with handling temperatures of propulsion batteries. It is to be understood that even
though propulsion batteries produce heat during operation, during certain weather
conditions and outside temperatures, the cooling system and the coolant may be used
for warming propulsion batteries. The application shall thus not be regarded as limited
to only cooling, but may also entail warming. Thus, the temperature of the coolant
provided to the propulsion batteries may be cooler than the temperature of the propulsion
batteries, but the temperatures of the coolant may also warmer than the temperatures
of the propulsion batteries.
[0023] One example of a distribution pipe circuit 10 of a vehicle propulsion battery cooling
system 8 for cooling propulsion batteries 12 is shown in Fig. 1. The distribution
pipe circuit 10 is fluidly connected to a main cooling system 14 that is configured
to regulate the temperature of a number of propulsion batteries arranged in a vehicle.
The main cooling system comprises a number of units for the temperature regulation
such as a temperature conditioning circuit. The temperature conditioning circuit may
comprise radiators, pumps, valves, coolers and heaters as well as regulating and control
means as well as sensors of different types. This type of temperature conditioning
circuit is well known in this technical field and will not be described in more detail.
Each propulsion battery comprises a plurality of battery cells encased in enclosure
forming a battery pack, which is the wording that is used in this application. It
is to be understood that propulsion batteries may have different layout and chemical
compositions, which is outside the scope of the present application. The important
aspect is that the cells of the battery packs can be temperature controlled.
[0024] From the main cooling system only two conduits 16, 18 are drawn to the location that
a cluster of propulsion battery packs 12 is located, one coolant inlet circuit 16
for incoming coolant and one coolant outlet circuit 18 for return coolant. The location
may be on the roof of a vehicle such as a public transport bus 50, see Fig. 5, i.e.
remotely from the main cooling system 14. The battery packs 12 comprise a large number
of battery cells encased in a suitable housing, whereby space for coolant is created
between the cells and the housing. The coolant is used for keeping the battery cells
in an even temperature during operation. The battery packs 12 are connected in appropriate
ways to an electrical machine 15 for propelling the vehicle. The connection to the
electrical machine and its controlling does not form part of the present application
and will not be discussed in detail in the following.
[0025] According to the application, the inlet conduit 16 is connected to an inlet port
20 of a first manifold section 22 of a coolant distribution arrangement 24 comprised
in the distribution pipe circuit 10, Fig. 1. The first manifold section 22 preferably
has an elongated hollow body 26, providing an elongated volume. The inlet port 20
is preferably positioned at one end of the body 26, whereby coolant entering the volume
will have a flow direction fd along the elongated body 26. The first coolant manifold
section 22 is further arranged with a number of outlet ports 28, the number corresponding
to the number of battery packs 12 that are to be cooled, preferably positioned along
the elongated body 26. Suitable conduits 30 are connected between the outlet ports
28 and the battery packs 12.
[0026] The coolant distribution arrangement 24 is further provided with a second manifold
section 32. The second manifold section 32 preferably also has an elongated hollow
body 34, providing an elongated volume. The second manifold section 32 is further
provided with a number of inlet ports 36, the number corresponding to the number of
battery packs 12. Suitable fluid conduits 37 are connected between the battery packs
12 and the inlet ports 36. The second manifold section 32 is further provided with
an outlet port 38, preferably positioned at one end of the body 34, to which outlet
port 38 the coolant outlet circuit 18 is connected for return of the coolant to the
main cooling system 14. A flow direction
fd in the elongated body 34 will be created from the inlet ports 36 to the outlet port
38.
[0027] As seen with this solution, the battery packs 12 are connected in parallel with the
first and the second manifold section 22, 32. The first manifold section 22 preferably
has a volume that creates an even pressure level from the inlet of coolant. This also
creates an even flow to all battery packs which is important for providing the same
temperature control in all battery packs of the circuit.
[0028] Further, as seen in Fig. 1, the first manifold section 22 is angled or inclined in
its extension in relation to a horizontal plane. The inlet port 20 is preferably positioned
in one end of the first manifold section, and more preferably in the lower end of
the inclined first manifold section. This provides the advantage that any air that
might be present in the incoming coolant will rise and will move along an upper area
of the volume of the first manifold section 22 up to the upper end of the inclined
first manifold section 22. Further, the outlet ports 28 to the battery packs 12 are
preferably placed in a lower section of the volume of the first manifold section 22
in order to avoid or minimize the risk of air entering the battery packs 12 that might
be present in the incoming coolant, since most of any air entering the volume of the
first manifold section 22 will rise to an upper part of the volume.
[0029] According to the application, in order to evacuate air that is present in the first
manifold section 22, a deairing outlet port 40 is arranged at the upper end of the
inclined first manifold section 22. Thus, the deairing outlet port 40 is placed downstream
of the outlet ports 28. The deairing outlet port 40 is fluidly connected to a deairing
inlet port 42 on the second manifold section via a connection 44, forming a deairing
bypass. The bypass connection 44 could for example be a suitable conduit such as a
hose.
[0030] Further, as seen in Fig. 1, the second manifold section 32 is also arranged angled
or inclined with respect to a horizontal plane. Here, the outlet port 38 for the return
of coolant is arranged at the upper end of the inclined second manifold 32. The deairing
inlet port 42 for the bypass connection 44 is positioned upstream of the outlet port
38 for the coolant as seen in the flow direction fd. Further, the deairing inlet port
42 for the bypass connection 44 is positioned downstream of the inlet ports 36 of
the battery packs 12. Thus, air that is transported from the first manifold section
22 to the second manifold section 32 via the bypass connection 44 will be introduced
into the flow of coolant returning from the second manifold section 32 to the main
cooling system and evacuated through the expansion tank of the main cooling system.
Further, any air present in the coolant from the battery packs 12 will be transported
by the flow of coolant returning from the second manifold section 32.
[0031] Even though the first and the second manifold sections 22, 32 have been shown to
be inclined, they could also be arranged vertical with the outlet port 40 of the bypass
connection 44 at the top of the first manifold section 22 and the outlet port 38 for
coolant return at the top of the second manifold section 32.
[0032] If more clusters of battery packs 12 are positioned remotely from the main cooling
system, an inter-connection may be provided. This may for example be the case with
articulated busses 60 used for public transport, Fig. 7, where one cluster 12 may
be arranged remotely on the roof of the front part while one cluster 12' may be arranged
remotely on the roof of the rear part. A first variant of such a solution is schematically
shown in Fig. 2 where two distribution circuits are connected in series. Here a return
circuit 18' from a first distribution circuit 10 is connected to an inlet port 20'
of a first manifold section 22' of a second distribution pipe circuit 10'. The second
distribution pipe circuit 10' may be arranged in the same manner as the first distribution
pipe circuit 10 with fluid conduits 30' from the first manifold section 22' to the
battery packs 12' of the second cluster. From the battery packs 12', fluid conduits
37' are connected to the second manifold section 32'. At the upper end of the second
manifold section 32', a return circuit 18 to the main cooling system 14 is provided.
As with the previously described embodiment with a single distribution pipe circuit,
also here a deairing bypass connection 44' is provided between the first and the second
manifold sections 22', 32', whereby air that is transported with the coolant from
the first distribution pipe circuit 10 will enter the first manifold section 22' of
the second distribution pipe circuit 10', and will be led via the bypass connection
44' to the second manifold section 32' of the second distribution pipe circuit 10'
and then transported back to the main cooling system with the return coolant as described
above.
[0033] Another variant is shown in Fig. 3, which is very similar regarding the layout as
the variant of Fig. 2. However, here two distribution circuits 10 and 10' are connected
in parallel. Thus, as seen in Fig. 3, the incoming circuit 16 is branched to provide
coolant to both first manifold sections 22 and 22'. In the same manner, the coolant
return from both second manifold sections 32 and 32' are connected to the return circuit
18. This setup might require an additional pump or a larger pump than for a single
circuit or for circuits connected in series.
[0034] With this solution, it is thus possible to connect and to cool several battery pack
clusters with the same main inlet and outlet conduits from the main cooling system.
Thus, even if there are several battery clusters arranged remotely from the cooling
system, it is not necessary to provide several inlet and outlet conduits which is
an advantage when taking into account the limited space available as well as the distances
between the battery pack clusters and the main cooling system.
[0035] In the above shown embodiments, the coolant distribution arrangement 24 has been
shown and described as two separate manifold sections with the bypass connection as
a separate conduit, but it is of course possible to provide the coolant distribution
arrangement as a single unit. Figure 3 shows a schematic example of such a unit 24".
Here a lower first part 22" of the unit 24" corresponds to the first manifold section
with the inlet port 20" from the main cooling system at a lower end. The outlet ports
28" for supplying coolant to the battery packs are arranged along a lower section
of the volume of the first part 22". An upper second part 32" of the unit 24" corresponds
to the second manifold section, having the inlet ports 36" for coolant returning from
the battery packs arranged along a lower section of the volume of the second part
32". At the upper end of the second part 32", an outlet port 38" for the return of
coolant to the main cooling system is provided. As seen in the figure, a passage 44"
is provided between the two parts 22", 32" in an upper area thereof, creating a bypass
connection.
[0036] Thus, any air entering the volume of the first part 22" will move along the upper
area of the volume of the first part" and will thus not be drawn into the flow of
coolant to the battery packs, at least not to any larger extent. Instead, the air
will flow through the bypass connection 44" into the volume of the second part 32"
adjacent the outlet port 38" for the return of coolant. Thus, the air will be drawn
together with the coolant out of the unit and be transported back to the cooling system
where it will be deaired via an expansion tank of the cooling system. This solution
provides a very compact yet effective solution both for the distribution of coolant
to a number of battery packs as well as handling any air included in the coolant without
air entering the battery packs.
[0037] In the foregoing, it has been mentioned that clusters of battery packs may be arranged
on the roof of a vehicle. However, it is possible to utilize the present application
where clusters of battery packs are placed in other positions in a vehicle, which
positions may be at some distance or remotely from the main cooling system. For instance,
in a long-distance bus or coach 70, some battery packs 12 may be placed under the
floor of the passenger compartment towards the front of the coach, where the main
cooling system 14 is situated in the rear of the coach as seen in Fig. 6. Also with
this situation, it is an advantage that as few conduits as possible are drawn through
the vehicle, since it will interfere with luggage space under the passenger compartment
and also lead to increased assembly time of the system as well as increased complexity.
As mentioned above, with the solution according to the present application, only two
conduits are needed for the supply of coolant to battery packs positioned remotely
from the main cooling system.
[0038] Another example where the present solution may be used is for trucks 80 and the like
heavy vehicles that are configured to be connected to and tow a trailer 82. The trailer
is often a separate unit that may be connected and disconnected to the truck. As seen
schematically in Fig. 8, one or several battery pack clusters 12 may be provided remotely
on the trailer in addition to battery packs mounted on the truck. The present application
may then be used for cooling of the battery packs on the trailer, and it is therefore
an advantage that only two conduits are arranged between the truck and the trailer.
[0039] It is to be understood that the embodiments described above and shown in the drawings
are to be regarded only as non-limiting examples and that the present application
can be modified in many ways within the scope of the patent claims.
1. A coolant distribution arrangement (24, 24', 24") for a vehicle propulsion battery
cooling system (8), the cooling system (8) comprising a coolant inlet circuit (16),
a coolant outlet circuit (18), and at least one coolant branch (30, 37), configured
to cool a set of propulsion battery packs (12, 12'), wherein
- the arrangement (24, 24', 24") comprises a first manifold section (22, 22', 22"),
which first manifold section (22, 22', 22") comprises:
- a coolant inlet (20, 20', 20") configured to receive coolant from the coolant inlet
circuit (16),
- supply outlets (28, 28', 28") configured to supply coolant to the at least one coolant
branch (30, 37; 30', 37'),
wherein the arrangement comprises a second manifold section (32, 32', 32"), which
second manifold section (32, 32', 32") comprises:
- receiving inlets (36, 36', 36") configured to receive coolant from the at least
one coolant branch (30, 37; 30', 37'),
- a coolant outlet (38, 38', 38") configured to return coolant to the coolant outlet
circuit (18), and
wherein the arrangement (24, 24', 24") comprises a deairing connection (44, 44', 44")
between the first manifold section (22, 22', 22") and the second manifold section
(32, 32', 32") configured to evacuate air from the first manifold section (22, 22',
22") to the second manifold section (32, 32', 32").
2. A coolant distribution arrangement (24, 24', 24") according to claim 1, wherein the
deairing connection (44, 44', 44") is arranged downstream of the supply outlets (28,
28', 28") of the first manifold section (22, 22', 22").
3. A coolant distribution arrangement (24, 24', 24") according to claim 2, wherein the
deairing connection (44, 44', 44"), when the arrangement (24, 24', 24") is attached
to a vehicle, is positioned higher than the supply outlets (28, 28', 28").
4. A coolant distribution arrangement (24, 24', 24") according to claim 2 or 3, wherein
the coolant inlet (20, 20', 20") is arranged upstream of said supply outlets (28,
28', 28").
5. A coolant distribution arrangement (24, 24', 24") according to any of the claims 2
to 4, wherein the deairing connection (44, 44', 44") is arranged downstream of the
receiving inlets (26, 26', 26") of the second manifold section (32, 32', 32").
6. A coolant distribution arrangement (24, 24', 24") according to claim 5, wherein the
deairing connection (44, 44', 44") is arranged upstream of the coolant outlet (28,
28', 28"), whereby air in the second manifold section (32, 32', 32") is evacuated
through the coolant outlet (28, 28', 28").
7. A coolant distribution arrangement (24, 24', 24") according to any of the claims 4
to 6, wherein the coolant outlet (28, 28', 28"), when the arrangement (24, 24', 24")
is attached to a vehicle, is positioned higher than the deairing connection (44, 44',
44").
8. A coolant distribution arrangement (24, 24') according to any of the preceding claims,
wherein the first and the second manifold sections (22, 22', 32, 32') are discrete
components and wherein the deairing connection (44, 44') comprises a separate conduit.
9. A coolant distribution arrangement (24") according to any of the preceding claims,
wherein the first and the second manifold sections (22", 32") form a single unit (24")
and wherein the deairing connection comprises a passage (44") provided in the unit
(24").
10. A vehicle propulsion battery cooling system (8) comprising:
- at least one distribution pipe circuit (10, 10') fluidly connected to a main cooling
system (14),
- at least one coolant branch (30, 37; 30', 37') configured to cool a set of propulsion
battery packs, and
- a coolant distribution arrangement (24, 24', 24") according to any of the preceding
claims.
11. A vehicle propulsion battery cooling system (8) according to claim 10, comprising
several distribution pipe circuits (10, 10') fluidly connected in series to the main
cooling system (14).
12. A vehicle propulsion battery cooling system (8) according to claim 10, comprising
several distribution pipe circuits (10, 10') fluidly connected in parallel to the
main cooling system (14).
13. A vehicle propulsion battery cooling system (8) according to claims 10 to12, wherein
the at least one distribution pipe circuit (10, 10') and the battery packs (12, 12')
are located remotely from the main cooling system.
14. A vehicle propulsion battery cooling system (8) according to claim 12, comprising
a single coolant inlet circuit (16) and a single coolant outlet circuit (18) for fluid
connection between the main cooling system (14) and the at least one distribution
pipe circuit (10. 10').
15. A vehicle comprising a main cooling system, a set of propulsion battery packs (12,
12') and a vehicle propulsion battery cooling system (8) according to any of the claims
10 - 14, wherein the vehicle propulsion battery cooling system (8) is configured to
cool the set of propulsion battery packs (12, 12').